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Is the Earth putting on weight....?

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ALanQIMan
599323.  Sat Aug 15, 2009 6:48 am Reply with quote

Everyone has a book in them, and everyone has some odd question which they canít answer. I have two such questions! Todayís the day I post them here.

As I understand it (which is hardly at all) sunlight is the transfer of energy from the burning sun to the Earth. Various biological mechanisms on Earth synthesise that energy in order to increase their mass. Does this mean that the overall body of matter of which the Earth is composed constantly increases, and if so, by how much? How much more mass does the Earth have now than it had, say, a million years ago?

 
bobwilson
599690.  Sat Aug 15, 2009 9:09 pm Reply with quote

Short answer - yes. Long answer will have to wait for another day. (and btw the biological mechanisms are negligible).

 
Posital
599728.  Sun Aug 16, 2009 3:02 am Reply with quote

Needs to be balanced with the atmosphere disappearing off into space.

I would think the odd meteor strike would make the effects melt into insignificance.

 
Davini994
600395.  Mon Aug 17, 2009 1:11 pm Reply with quote

Plants aren't manufacturing matter from photons through E = mc^2 though.

 
Posital
600550.  Mon Aug 17, 2009 7:02 pm Reply with quote

Davini994 wrote:
Plants aren't manufacturing matter from photons through E = mc^2 though.
I believe they are.
The em energy is effectively being stored by building complex molecules.
There must be a mass difference between the resultant complex molecules and its components. Albeit tiny.

 
bobwilson
600554.  Mon Aug 17, 2009 7:06 pm Reply with quote

I thought that too Posital. The energy from sunlight is converted into mass (inefficiently admittedly) by plants.

 
ColinM
600614.  Tue Aug 18, 2009 3:14 am Reply with quote

I wouldn't say they manufacture matter; they don't make any new atoms. They do get slightly heavier, but so does anything if you make it hot. And on the subject of hot, the Earth radiates heat (and therefore mass) as well; presumably roughly as much as it gains from the sun.

I'd guess that the gradual loss of atmosphere is a much bigger effect, though I don't really know how quickly it happens. Then there are solar winds, which I guess will add a few atoms here and there.

I don't think there's a lot in it either way.

 
Davini994
600808.  Tue Aug 18, 2009 9:48 am Reply with quote

Yes to the complex molecules thing, but that's not why plants get bigger. They get bigger because they are using material around them. The increase in weight due to rearranging the atomic structure is negligible.

 
Posital
600902.  Tue Aug 18, 2009 2:38 pm Reply with quote

Davini994 wrote:
Yes to the complex molecules thing, but that's not why plants get bigger. They get bigger because they are using material around them. The increase in weight due to rearranging the atomic structure is negligible.
Don't think anyone was saying the gain in mass was observable - or to do with atomic structure. It's the energy stored in the chemical bonds that make the imperceivable difference.

Atomic plants - whatever next.

 
Davini994
600969.  Tue Aug 18, 2009 4:43 pm Reply with quote

Yes, I meant rearranging the atoms, not rearranging the atomic structure as I wrote. As I'm sure you could have fathomed.

As the original question was "does the weight gain of plants when they grow in sunlight mean a gain in mass of the planet", then pointing out that they aren't making the matter from the energy, but getting it from elsewhere, is a sensible contribution.

As was my first point, that the mass difference of a complex chemical structure to its components is an extremely small amount. That's the important point to grasp with the question.

Edited to remove upsetting apostrophe.


Last edited by Davini994 on Wed Aug 19, 2009 9:40 pm; edited 1 time in total

 
Posital
600978.  Tue Aug 18, 2009 4:58 pm Reply with quote

Davini994 wrote:
Plants aren't manufacturing matter from photons through E = mc^2 though.

This was your first point.

Sorry - I guess I'm struggling with my fathoming.

Is that the time?

 
Davini994
601147.  Wed Aug 19, 2009 7:14 am Reply with quote

Posital wrote:
This was your first point.

So as I said then.

Quote:
Sorry - I guess I'm struggling with my fathoming.

If you tried fathoming, rather than trying to be as annoying as possible, you might do better. Who knows? You might eventually even write a post interesting enough to be worth reading.

 
Jenny
601265.  Wed Aug 19, 2009 12:52 pm Reply with quote

Touchy, touchy, chaps. No need for aggro.

 
Posital
601303.  Wed Aug 19, 2009 1:42 pm Reply with quote

lol - step away from the argument... put your hands in the air where we can see them...

I guess admitting we're having difficulty understanding something isn't always welcome. Oh well.

 
Susannah Dingley
601422.  Wed Aug 19, 2009 5:05 pm Reply with quote

Davini994 wrote:
As was my first point, that the mass difference of a complex chemical structure to it's components is an extremely small amount. That's the important point to grasp with the question.

    its = belonging to it
    itís = it is

 

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